/*
 * Created on 2005-8-29
 * Last modified on 2008-4-18
 * Last modified by Huangfu
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package com.yeqiangwei.commons.ip;

import org.apache.log4j.Logger;

/*
* LumaQQ - Java QQ Client
*
* Copyright (C) 2004 luma <stubma@163.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/


import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteOrder;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;

/**
 * <pre>
 * 用来读取QQwry.dat文件，以根据ip获得朋友位置，QQwry.dat的格式是
 * 一. 文件头，共8字节
 * 	   1. 第一个起始IP的绝对偏移， 4字节
 *     2. 最后一个起始IP的绝对偏移， 4字节
 * 二. "结束地址/国家/区域"记录区
 *     四字节ip地址后跟的每一条记录分成两个部分
 *     1. 国家记录
 *     2. 地区记录
 *     但是地区记录是不一定有的。而且国家记录和地区记录都有两种形式
 *     1. 以0结束的字符串
 *     2. 4个字节，一个字节可能为0x1或0x2
 * 		  a. 为0x1时，表示在绝对偏移后还跟着一个区域的记录，注意是绝对偏移之后，而不是这四个字节之后
 *        b. 为0x2时，表示在绝对偏移后没有区域记录
 *        不管为0x1还是0x2，后三个字节都是实际国家名的文件内绝对偏移
 * 		  如果是地区记录，0x1和0x2的含义不明，但是如果出现这两个字节，也肯定是跟着3个字节偏移，如果不是
 *        则为0结尾字符串
 * 三. "起始地址/结束地址偏移"记录区
 *     1. 每条记录7字节，按照起始地址从小到大排列
 *        a. 起始IP地址，4字节
 *        b. 结束ip地址的绝对偏移，3字节
 *
 * 注意，这个文件里的ip地址和所有的偏移量均采用little-endian格式，而java是采用
 * big-endian格式的，要注意转换
 * </pre>
 *
 * @author 马若劼
 */
public class IPSeeker {
	/**
	 * Logger for this class
	 */
	private static final Logger logger = Logger.getLogger(IPSeeker.class);
	
	private static final String EMPTY = "";

	/**
	 * <pre>
	 * 用来封装ip相关信息，目前只有两个字段，ip所在的国家和地区
	 * </pre>
	 *
	 * @author 马若劼
	 */
	private class IPLocation {
		/**
		 * Logger for this class
		 */
		private final Logger logger = Logger.getLogger(IPLocation.class);

		public String country;
		public String area;

		public IPLocation() {
		    country = area = EMPTY;
		}

		public IPLocation getCopy() {
			if(logger.isDebugEnabled())
			{
				logger.debug("getCopy() - start");
			}
		    IPLocation ret = new IPLocation();
		    ret.country = country;
		    ret.area = area;

			if(logger.isDebugEnabled())
			{
				logger.debug("getCopy() - end");
			}
		    return ret;
		}
	}
	
	private static String IP_FILE = null;

	public static String REAL_PATH = null;
	
	public static String WEB_INF_PATH = null;
	

	static{
		if (REAL_PATH == null) {
			REAL_PATH = com.yeqiangwei.commons.util.Constants.ROOT_PATH;
		}
		if(WEB_INF_PATH == null){
			WEB_INF_PATH = com.yeqiangwei.commons.util.Constants.WEB_INF_PATH;
		}
		if(IP_FILE == null){
			IP_FILE = WEB_INF_PATH + "index" + File.separator + "QQWry.dat";
		}
		if(logger.isDebugEnabled()){
			logger.debug("...... " + IP_FILE);
		}
	}
	
	// 一些固定常量，比如记录长度等等
	private static final int IP_RECORD_LENGTH = 7;
	private static final byte AREA_FOLLOWED = 0x01;
	private static final byte NO_AREA = 0x2;

 	// 用来做为cache，查询一个ip时首先查看cache，以减少不必要的重复查找
	private Hashtable<String,IPLocation> ipCache;
	// 随机文件访问类
	private RandomAccessFile ipFile;
	// 内存映射文件
	private MappedByteBuffer mbb;
	// 单一模式实例
	private static IPSeeker instance = new IPSeeker();
	// 起始地区的开始和结束的绝对偏移
	private long ipBegin, ipEnd;
	// 为提高效率而采用的临时变量
	private IPLocation loc;
	private byte[] buf;
	private byte[] b4;
	private byte[] b3;

	/**
	 * 私有构造函数
	 */
	private IPSeeker()  {
		ipCache = new Hashtable<String,IPLocation>();
		loc = new IPLocation();
		buf = new byte[100];
		b4 = new byte[4];
		b3 = new byte[3];
		try {
			if(logger.isDebugEnabled())
			{
				logger.debug("IPSeeker() - " + IP_FILE);
			}
			ipFile = new RandomAccessFile(IP_FILE, "r");
		} catch (FileNotFoundException e) {
			logger.error("IPSeeker()", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("IPSeeker() - "
						+ IPSeeker.class.getResource("/QQWry.dat").toString());
			}
			if(logger.isDebugEnabled())
			{
				logger.debug("IPSeeker() - " + IP_FILE);
			}
			if(logger.isDebugEnabled())
			{
				logger.debug("IPSeeker() - IP地址信息文件没有找到，IP显示功能将无法使用");
			}
			ipFile = null;

		}
		// 如果打开文件成功，读取文件头信息
		if(ipFile != null) {
			try {
				ipBegin = readLong4(0);
				ipEnd = readLong4(4);
				if(ipBegin == -1 || ipEnd == -1) {
					ipFile.close();
					ipFile = null;
				}
			} catch (IOException e) {
				logger.error("IPSeeker()", e);

				if(logger.isDebugEnabled())
				{
					logger.debug("IPSeeker() - IP地址信息文件格式有错误，IP显示功能将无法使用");
				}
				ipFile = null;
			}
		}
		
	}

	/**
	 * @return 单一实例
	 */
	public static IPSeeker getInstance() {
		if(logger.isDebugEnabled())
		{
			logger.debug("getInstance() - start");
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("getInstance() - end");
		}
		
		return instance;
	}

	/**
	 * 给定一个地点的不完全名字，得到一系列包含s子串的IP范围记录
	 * @param s 地点子串
	 * @return 包含IPEntry类型的List
	 */
	public List<IPEntry> getIPEntriesDebug(String s) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getIPEntriesDebug(String) - start");
		}

	    List<IPEntry> ret = new ArrayList<IPEntry>();
	    long endOffset = ipEnd + 4;
	    for(long offset = ipBegin + 4; offset <= endOffset; offset += IP_RECORD_LENGTH) {
	        // 读取结束IP偏移
	        long temp = readLong3(offset);
	        // 如果temp不等于-1，读取IP的地点信息
	        if(temp != -1) {
	            IPLocation loc = getIPLocation(temp);
	            // 判断是否这个地点里面包含了s子串，如果包含了，添加这个记录到List中，如果没有，继续
	            if(loc.country.indexOf(s) != -1 || loc.area.indexOf(s) != -1) {
	                IPEntry entry = new IPEntry();
	                entry.country = loc.country;
	                entry.area = loc.area;
	                // 得到起始IP
	    	        readIP(offset - 4, b4);
	                entry.beginIp = IPUtils.getIpStringFromBytes(b4);
	                // 得到结束IP
	                readIP(temp, b4);
	                entry.endIp = IPUtils.getIpStringFromBytes(b4);
	                // 添加该记录
	                ret.add(entry);
	            }
	        }
	    }

		if(logger.isDebugEnabled())
		{
			logger.debug("getIPEntriesDebug(String) - end");
		}
	    return ret;
	}

	/**
	 * 给定一个地点的不完全名字，得到一系列包含s子串的IP范围记录
	 * @param s 地点子串
	 * @return 包含IPEntry类型的List
	 */
	public List<IPEntry> getIPEntries(String s) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getIPEntries(String) - start");
		}

	    List<IPEntry> ret = new ArrayList<IPEntry>();
	    try {
	        // 映射IP信息文件到内存中
	        if(mbb == null) {
			    FileChannel fc = ipFile.getChannel();
	            mbb = fc.map(FileChannel.MapMode.READ_ONLY, 0, ipFile.length());
	            mbb.order(ByteOrder.LITTLE_ENDIAN);
	        }

		    int endOffset = (int)ipEnd;
            for(int offset = (int)ipBegin + 4; offset <= endOffset; offset += IP_RECORD_LENGTH) {
                int temp = readInt3(offset);
                if(temp != -1) {
    	            IPLocation loc = getIPLocation(temp);
    	            // 判断是否这个地点里面包含了s子串，如果包含了，添加这个记录到List中，如果没有，继续
    	            if(loc.country.indexOf(s) != -1 || loc.area.indexOf(s) != -1) {
    	                IPEntry entry = new IPEntry();
    	                entry.country = loc.country;
    	                entry.area = loc.area;
    	                // 得到起始IP
    	    	        readIP(offset - 4, b4);
    	                entry.beginIp = IPUtils.getIpStringFromBytes(b4);
    	                // 得到结束IP
    	                readIP(temp, b4);
    	                entry.endIp = IPUtils.getIpStringFromBytes(b4);
    	                // 添加该记录
    	                ret.add(entry);
    	            }
                }
            }
        } catch (IOException e) {
			logger.error("getIPEntries(String)", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("getIPEntries() - " + e.getMessage());
			}
        }

		if(logger.isDebugEnabled())
		{
			logger.debug("getIPEntries(String) - end");
		}
        return ret;
	}

	/**
	 * 从内存映射文件的offset位置开始的3个字节读取一个int
	 * @param offset
	 * @return
	 */
	private int readInt3(int offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readInt3(int) - start");
		}

	    mbb.position(offset);
		int returnint = mbb.getInt() & 0x00FFFFFF;
		if(logger.isDebugEnabled())
		{
			logger.debug("readInt3(int) - end");
		}
	    return returnint;
	}

	/**
	 * 从内存映射文件的当前位置开始的3个字节读取一个int
	 * @return
	 */
	private int readInt3() {
		if(logger.isDebugEnabled())
		{
			logger.debug("readInt3() - start");
		}

		int returnint = mbb.getInt() & 0x00FFFFFF;
		if(logger.isDebugEnabled())
		{
			logger.debug("readInt3() - end");
		}
	    return returnint;
	}

	/**
	 * 根据IP得到国家名
	 * @param ip ip的字节数组形式
	 * @return 国家名字符串
	 */
	public String getState(byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getState(byte[]) - start");
		}
		
		// 检查ip地址文件是否正常
		if(ipFile == null) return "错误的IP数据库文件";
		// 保存ip，转换ip字节数组为字符串形式
		String ipStr = IPUtils.getIpStringFromBytes(ip);
		
		// 先检查cache中是否已经包含有这个ip的结果，没有再搜索文件
		if(ipCache.containsKey(ipStr)) {
			IPLocation loc = (IPLocation)ipCache.get(ipStr);
			if(logger.isDebugEnabled())
			{
				logger.debug("getState(byte[]) - end");
			}
			return loc.country;
		} else {
			IPLocation loc = getIPLocation(ip);
			ipCache.put(ipStr, loc.getCopy());
			if(logger.isDebugEnabled())
			{
				logger.debug("getState(byte[]) - end");
			}
			return loc.country;
		}
	}

	/**
	 * 根据IP得到国家名
	 * @param ip IP的字符串形式
	 * @return 国家名字符串
	 */
	public String getState(String ip) {
		
		if(logger.isDebugEnabled())
		{
			logger.debug("getState(String) - start");
		}
		
		String returnString = getState(IPUtils.getIpByteArrayFromString(ip));
		
		if(logger.isDebugEnabled())
		{
			logger.debug("getState(String) - end");
		}
	    return returnString;
	}

	/**
	 * 根据IP得到地区名
	 * @param ip ip的字节数组形式
	 * @return 地区名字符串
	 */
	public String getCity(byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getCity(byte[]) - start");
		}

		// 检查ip地址文件是否正常
		if(ipFile == null) return "错误的IP数据库文件";
		// 保存ip，转换ip字节数组为字符串形式
		String ipStr = IPUtils.getIpStringFromBytes(ip);
		// 先检查cache中是否已经包含有这个ip的结果，没有再搜索文件
		if(ipCache.containsKey(ipStr)) {
			IPLocation loc = (IPLocation)ipCache.get(ipStr);

			if(logger.isDebugEnabled())
			{
				logger.debug("getCity(byte[]) - end");
			}
			return loc.area;
		} else {
			IPLocation loc = getIPLocation(ip);
			ipCache.put(ipStr, loc.getCopy());

			if(logger.isDebugEnabled())
			{
				logger.debug("getCity(byte[]) - end");
			}
			return loc.area;
		}
	}

	/**
	 * 根据IP得到地区名
	 * @param ip IP的字符串形式
	 * @return 地区名字符串
	 */
	public String getCity(String ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getCity(String) - start");
		}

		String returnString = getCity(IPUtils.getIpByteArrayFromString(ip));
		if(logger.isDebugEnabled())
		{
			logger.debug("getCity(String) - end");
		}
	    return returnString;
	}

	/**
	 * 根据ip搜索ip信息文件，得到IPLocation结构，所搜索的ip参数从类成员ip中得到
	 * @param ip 要查询的IP
	 * @return IPLocation结构
	 */
	private IPLocation getIPLocation(byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getIPLocation(byte[]) - start");
		}

		IPLocation info = null;
		long offset = locateIP(ip);
		if(offset != -1)
			info = getIPLocation(offset);
		if(info == null) {
			info = new IPLocation();
			info.country = "未知国家";
			info.area = "未知地区";
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("getIPLocation(byte[]) - end");
		}
		return info;
	}

	/**
	 * 从offset位置读取4个字节为一个long，因为java为big-endian格式，所以没办法
	 * 用了这么一个函数来做转换
	 * @param offset
	 * @return 读取的long值，返回-1表示读取文件失败
	 */
	private long readLong4(long offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readLong4(long) - start");
		}

		long ret = 0;
		try {
			ipFile.seek(offset);
			ret |= (ipFile.readByte() & 0xFF);
			ret |= ((ipFile.readByte() << 8) & 0xFF00);
			ret |= ((ipFile.readByte() << 16) & 0xFF0000);
			ret |= ((ipFile.readByte() << 24) & 0xFF000000);

			if(logger.isDebugEnabled())
			{
				logger.debug("readLong4(long) - end");
			}
			return ret;
		} catch (IOException e) {
			logger.error("readLong4(long)", e);

			long returnlong = -1;
			if(logger.isDebugEnabled())
			{
				logger.debug("readLong4(long) - end");
			}
			return returnlong;
		}
	}

	/**
	 * 从offset位置读取3个字节为一个long，因为java为big-endian格式，所以没办法
	 * 用了这么一个函数来做转换
	 * @param offset
	 * @return 读取的long值，返回-1表示读取文件失败
	 */
	private long readLong3(long offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readLong3(long) - start");
		}

		long ret = 0;
		try {
			ipFile.seek(offset);
			ipFile.readFully(b3);
			ret |= (b3[0] & 0xFF);
			ret |= ((b3[1] << 8) & 0xFF00);
			ret |= ((b3[2] << 16) & 0xFF0000);

			if(logger.isDebugEnabled())
			{
				logger.debug("readLong3(long) - end");
			}
			return ret;
		} catch (IOException e) {
			logger.error("readLong3(long)", e);

			long returnlong = -1;
			if(logger.isDebugEnabled())
			{
				logger.debug("readLong3(long) - end");
			}
			return returnlong;
		}
	}

	/**
	 * 从当前位置读取3个字节转换成long
	 * @return
	 */
	private long readLong3() {
		if(logger.isDebugEnabled())
		{
			logger.debug("readLong3() - start");
		}

		long ret = 0;
		try {
			ipFile.readFully(b3);
			ret |= (b3[0] & 0xFF);
			ret |= ((b3[1] << 8) & 0xFF00);
			ret |= ((b3[2] << 16) & 0xFF0000);

			if(logger.isDebugEnabled())
			{
				logger.debug("readLong3() - end");
			}
			return ret;
		} catch (IOException e) {
			logger.error("readLong3()", e);

			long returnlong = -1;
			if(logger.isDebugEnabled())
			{
				logger.debug("readLong3() - end");
			}
			return returnlong;
		}
	}

	/**
	 * 从offset位置读取四个字节的ip地址放入ip数组中，读取后的ip为big-endian格式，但是
	 * 文件中是little-endian形式，将会进行转换
	 * @param offset
	 * @param ip
	 */
	private void readIP(long offset, byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readIP(long, byte[]) - start");
		}

		try {
			ipFile.seek(offset);
			ipFile.readFully(ip);
			byte temp = ip[0];
			ip[0] = ip[3];
			ip[3] = temp;
			temp = ip[1];
			ip[1] = ip[2];
			ip[2] = temp;
		} catch (IOException e) {
			logger.error("readIP(long, byte[])", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("readIP() - " + e.getMessage());
			}
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("readIP(long, byte[]) - end");
		}
	}

	/**
	 * 从offset位置读取四个字节的ip地址放入ip数组中，读取后的ip为big-endian格式，但是
	 * 文件中是little-endian形式，将会进行转换
	 * @param offset
	 * @param ip
	 */
	private void readIP(int offset, byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readIP(int, byte[]) - start");
		}

	    mbb.position(offset);
	    mbb.get(ip);
		byte temp = ip[0];
		ip[0] = ip[3];
		ip[3] = temp;
		temp = ip[1];
		ip[1] = ip[2];
		ip[2] = temp;

		if(logger.isDebugEnabled())
		{
			logger.debug("readIP(int, byte[]) - end");
		}
	}

	/**
	 * 把类成员ip和beginIp比较，注意这个beginIp是big-endian的
	 * @param ip 要查询的IP
	 * @param beginIp 和被查询IP相比较的IP
	 * @return 相等返回0，ip大于beginIp则返回1，小于返回-1。
	 */
	private int compareIP(byte[] ip, byte[] beginIp) {
		if(logger.isDebugEnabled())
		{
			logger.debug("compareIP(byte[], byte[]) - start");
		}

		for(int i = 0; i < 4; i++) {
			int r = compareByte(ip[i], beginIp[i]);
			if(r != 0)
				return r;
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("compareIP(byte[], byte[]) - end");
		}
		return 0;
	}

	/**
	 * 把两个byte当作无符号数进行比较
	 * @param b1
	 * @param b2
	 * @return 若b1大于b2则返回1，相等返回0，小于返回-1
	 */
	private int compareByte(byte b1, byte b2) {
		if(logger.isDebugEnabled())
		{
			logger.debug("compareByte(byte, byte) - start");
		}

		if((b1 & 0xFF) > (b2 & 0xFF)) // 比较是否大于
			return 1;
		else if((b1 ^ b2) == 0)// 判断是否相等
			return 0;
		else
			return -1;
	}

	/**
	 * 这个方法将根据ip的内容，定位到包含这个ip国家地区的记录处，返回一个绝对偏移
	 * 方法使用二分法查找。
	 * @param ip 要查询的IP
	 * @return 如果找到了，返回结束IP的偏移，如果没有找到，返回-1
	 */
	private long locateIP(byte[] ip) {
		if(logger.isDebugEnabled())
		{
			logger.debug("locateIP(byte[]) - start");
		}

		long m = 0;
		int r;
		// 比较第一个ip项
		readIP(ipBegin, b4);
		r = compareIP(ip, b4);
		if(r == 0) return ipBegin;
		else if(r < 0) return -1;
		// 开始二分搜索
		for(long i = ipBegin, j = ipEnd; i < j; ) {
			m = getMiddleOffset(i, j);
			readIP(m, b4);
			r = compareIP(ip, b4);
			// log.debug(IPUtils.getIpStringFromBytes(b));
			if(r > 0)
				i = m;
			else if(r < 0) {
				if(m == j) {
					j -= IP_RECORD_LENGTH;
					m = j;
				} else
					j = m;
			} else
				return readLong3(m + 4);
		}
		// 如果循环结束了，那么i和j必定是相等的，这个记录为最可能的记录，但是并非
		//     肯定就是，还要检查一下，如果是，就返回结束地址区的绝对偏移
		m = readLong3(m + 4);
		readIP(m, b4);
		r = compareIP(ip, b4);
		if(r <= 0) return m;
		else return -1;
	}

	/**
	 * 得到begin偏移和end偏移中间位置记录的偏移
	 * @param begin
	 * @param end
	 * @return
	 */
	private long getMiddleOffset(long begin, long end) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getMiddleOffset(long, long) - start");
		}

		long records = (end - begin) / IP_RECORD_LENGTH;
		records >>= 1;
		if(records == 0) records = 1;
		long returnlong = begin + records * IP_RECORD_LENGTH;
		if(logger.isDebugEnabled())
		{
			logger.debug("getMiddleOffset(long, long) - end");
		}
		return returnlong;
	}

	/**
	 * 给定一个ip国家地区记录的偏移，返回一个IPLocation结构
	 * @param offset
	 * @return
	 */
	private IPLocation getIPLocation(long offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getIPLocation(long) - start");
		}
		try {
			// 跳过4字节ip
			ipFile.seek(offset + 4);
			// 读取第一个字节判断是否标志字节
			byte b = ipFile.readByte();
			if(b == AREA_FOLLOWED) {
				// 读取国家偏移
				long countryOffset = readLong3();
				// 跳转至偏移处
				ipFile.seek(countryOffset);
				// 再检查一次标志字节，因为这个时候这个地方仍然可能是个重定向
				b = ipFile.readByte();
				if(b == NO_AREA) {
					loc.country = readString(readLong3());
					ipFile.seek(countryOffset + 4);
				} else
					loc.country = readString(countryOffset);
				// 读取地区标志
				loc.area = readArea(ipFile.getFilePointer());
			} else if(b == NO_AREA) {
				loc.country = readString(readLong3());
				loc.area = readArea(offset + 8);
			} else {
				loc.country = readString(ipFile.getFilePointer() - 1);
				loc.area = readArea(ipFile.getFilePointer());
			}

			if(logger.isDebugEnabled())
			{
				logger.debug("getIPLocation(long) - end");
			}
			return loc;
		} catch (IOException e) {
			logger.error("getIPLocation(long)", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("getIPLocation(long) - end");
			}
			return null;
		}
		
	}

	/**
	 * @param offset
	 * @return
	 */
	private IPLocation getIPLocation(int offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("getIPLocation(int) - start");
		}
		// 跳过4字节ip
	    mbb.position(offset + 4);
		// 读取第一个字节判断是否标志字节
		byte b = mbb.get();
		if(b == AREA_FOLLOWED) {
			// 读取国家偏移
			int countryOffset = readInt3();
			// 跳转至偏移处
			mbb.position(countryOffset);
			// 再检查一次标志字节，因为这个时候这个地方仍然可能是个重定向
			b = mbb.get();
			if(b == NO_AREA) {
				loc.country = readString(readInt3());
				mbb.position(countryOffset + 4);
			} else
				loc.country = readString(countryOffset);
			// 读取地区标志
			loc.area = readArea(mbb.position());
		} else if(b == NO_AREA) {
			loc.country = readString(readInt3());
			loc.area = readArea(offset + 8);
		} else {
			loc.country = readString(mbb.position() - 1);
			loc.area = readArea(mbb.position());
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("getIPLocation(int) - end");
		}
		return loc;
	}

	/**
	 * 从offset偏移开始解析后面的字节，读出一个地区名
	 * @param offset
	 * @return 地区名字符串
	 * @throws IOException
	 */
	private String readArea(long offset) throws IOException {
		if(logger.isDebugEnabled())
		{
			logger.debug("readArea(long) - start");
		}

		ipFile.seek(offset);
		byte b = ipFile.readByte();
		if(b == 0x01 || b == 0x02) {
			long areaOffset = readLong3(offset + 1);
			if(areaOffset == 0)
				return "未知地区";
			else
				return readString(areaOffset);
		} else
			return readString(offset);
	}

	/**
	 * @param offset
	 * @return
	 */
	private String readArea(int offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readArea(int) - start");
		}

		mbb.position(offset);
		byte b = mbb.get();
		if(b == 0x01 || b == 0x02) {
			int areaOffset = readInt3();
			if(areaOffset == 0)
				return "未知地区";
			else
				return readString(areaOffset);
		} else
			return readString(offset);
	}

	/**
	 * 从offset偏移处读取一个以0结束的字符串
	 * @param offset
	 * @return 读取的字符串，出错返回空字符串
	 */
	private String readString(long offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readString(long) - start");
		}

		try {
			ipFile.seek(offset);
			int i;
			for(i = 0, buf[i] = ipFile.readByte(); buf[i] != 0; buf[++i] = ipFile.readByte());
			if(i != 0)
			    return IPUtils.getString(buf, 0, i, "GBK");
		} catch (IOException e) {
			logger.error("readString(long)", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("readString() - " + e.getMessage());
			}
		}

		if(logger.isDebugEnabled())
		{
			logger.debug("readString(long) - end");
		}
		return "";
	}

	/**
	 * 从内存映射文件的offset位置得到一个0结尾字符串
	 * @param offset
	 * @return
	 */
	private String readString(int offset) {
		if(logger.isDebugEnabled())
		{
			logger.debug("readString(int) - start");
		}

	    try {
			mbb.position(offset);
			int i;
			for(i = 0, buf[i] = mbb.get(); buf[i] != 0; buf[++i] = mbb.get());
			if(i != 0)
			    return IPUtils.getString(buf, 0, i, "GBK");
	    } catch (IllegalArgumentException e) {
			logger.error("readString(int)", e);

			if(logger.isDebugEnabled())
			{
				logger.debug("readString() - " + e.getMessage());
			}
	    }

		if(logger.isDebugEnabled())
		{
			logger.debug("readString(int) - end");
		}
	    return "";
	}

	public String getAddress(String ip){
		if(logger.isDebugEnabled())
		{
			logger.debug("getAddress(String) - start");
		}
		
		String country = getState(ip);
		String area = getCity(ip).equals("www.YeQiangWei.com")?"":getCity(ip);
        String address = country+" "+area;
		String returnString = address.trim();
		if(logger.isDebugEnabled())
		{
			logger.debug("getAddress(String) - end");
		}
		return returnString;
	}
	
	public IPModel getIPModel(String ip){
		if(logger.isDebugEnabled())
		{
			logger.debug("getAddress(String) - start");
		}
		String state = getState(ip);
		String city = getCity(ip).equals("www.YeQiangWei.com")?"":getCity(ip);
        //String address = country+" "+area;
		//String returnString = address.trim();
		IPModel model = new IPModel();
		model.setIp(ip);
		model.setState(state);
		model.setCity(city);
		//model.setCity();
		return model;
	}
	
	/**
	 * 主要用于将纯真库IP地址中文按Lucene的分词方法切分便于索引查找
	 * @param ip
	 * @return
	 * @throws IOException 
	 */
/*	public List<String> IPParser(String ip){
		if(Validator.isEmpty(ip)){
			return null;
		}		
		IPSeeker ipseeker = IPSeeker.getInstance();
		IPModel ipmodel= ipseeker.getIPModel(ip);
		String address = ipmodel.getState();
		if(Validator.isEmpty(address)){
			return null;
		}else{
			address = address.replaceAll("省","").replaceAll("市","");
		}
		List<String> list = null;
		Token[] tokens;
		try {
			tokens = AnalyzerUtils.tokensFromAnalysis(AnalyzerFactory.getAnalyzer(), address);
			if(!Validator.isEmpty(tokens)){
				list = new ArrayList<String>();
				for (int i = 0; i < tokens.length; i++) {
					String temp = tokens[i].termText();
					list.add(temp);
					//System.out.println(temp);
				}
			}
		} catch (IOException e) {
			logger.error(e.toString());
		}
		return list;
	}*/
	
/*	public static void main(String args[])
	{
	    IPSeeker ip = new IPSeeker();
	    List<String> m = ip.IPParser("218.25.62.58");
	    System.out.println(m.get(0)); 
	    
	}*/
}
